Span Bridge Structures Research Articles

Calculation method for a steel-reinforced concrete bridge span structure with material separation along the neutral axis

Introduction. In steel-reinforced concrete spans, the strength of reinforced concrete is not fully used due to the twostage inclusion of the cross section in the work and the irrational distribution of materials in the section. To increase the efficiency of the materials used, it is proposed to combine the steel and reinforced concrete parts along the neutral axis of the cross section. With such a cross-section design, the steel will always be in the tension zone, and the concrete in the compression zone. It is possible to implement such a design by constructing a span in one stage from prefabricated steel-reinforced concrete blocks.Materials and methods. It is possible to implement the calculation method with the separation of the material along the neutral axis when organizing the installation of the span structure in one stage, assuming that the section of the span structure operates in the elastic stage and following the laws of structural mechanics. To cover the features of the calculation of split and continuous span structures, a cantilever-beam static scheme was adopted.Results. The presented results of analytical calculations make it possible to estimate the consumption of materials in the manufacture of the span. The steel consumption of the span under study is 6.12 t/lm, the reinforced concrete consumption is 6.54 m3/lm.Installation of the span. The installation of the span is described, considering the design features.Conclusions. The optimal static layout of the span structure has been determined. A method for calculating a steel-reinforced concrete span with material separation along the neutral axis has been developed. An analytical calculation was performed to select the geometric parameters of the cross sections of the span.

Study on the application of TLS for bridge deflection inspection in Vietnam

Inspecting defects, geometric size discrepancies compared to the design profile, and displacement under theload of the bridge structure aims to gather information and current data before putting the bridge into operation. However, the quality of inspection on the structure size performed by traditional methods usually takes time consuming and potentially unsafe due to difficulties in accessing because the bridge dimension is high and the rugged terrain is challenging, especially with bridges crossing rivers, deep valleys, etc. Therefore, applying modern, effective, and reliable inspection methods is essentially required. The Terrestrial Laser Scanner (TLS) is a technique to quickly and accurately gather topographic data points of objects’ surfaces. TLS is applied in many survey fields, including surveying the structure of bridge engineering. To evaluate the effectiveness of applying TLS, the research conducted a determination of the main span P61-62’s deflection of the balance casting bridge crossing the Vong intersection of the urban traffic bridge project Ring Road 2, Hanoi city during static load testing. Three methods to determine the deflection of the bridge span structure were implemented (1) Using dial indicators; (2) Using a total station to measure points reflecting attached to the structure of the bridge girder; (3) Applying TLS to inspect the structure at the time of no load and load. The results led to the conclusion that TLS methodology facilitates the determination of the bridge deflection with acceptable accuracy.

ДОСЛІДЖЕННЯ НАПРУЖЕНО-ДЕФОРМОВАНОГО СТАНУ ЗАЛІЗОБЕТОННОЇ МОНОЛІТНОЇ ПОПЕРЕДНЬО НАПРУЖЕНОЇ ПРОГОНОВОЇ БУДОВИ ШЛЯХОПРОВОДУ

Introduction. The experience of operation of reinforced concrete span structures of bridges from the time of their use shows the need for their constant improvement. Due to the use of pre-tensioning of reinforcement in reinforced concrete span structures of bridges, it was possible to increase the crack resistance of such structures and operational reliability. This is especially relevant when it is necessary to increase the length of spans of reinforced concrete span structures. Problems Statement. The use of monolithic prestressed span structures with tension on concrete (post-tensioned systems) is the newest for Ukraine. They have many advantages compared to prefabricated prestressed reinforced concrete. But it is necessary to solve a number of problems in the design and construction of such structures in order to achieve the efficiency of structures that would serve the designed term, using all their advantages. Therefore, the study of such structures, assessment of their stress-strain state will allow in the future to find solutions for their improvement, development of appropriate calculation recommendations, construction of such structures. Purpose. Study of the stress-strain state of the structure of the monolithic non-separated prestressed span structure of the overpass with tension on concrete (post-tensioned system) in the city of Kherson.

ДИНАМІЧНІ ВИПРОБУВАННЯ МОСТІВ ІМПУЛЬСНИМ НАВАНТАЖЕННЯМ

Introduction. This article deals with the practice of applying the method of dynamic testing of bridges, namely, modal control using impulse loading. The possibilities of this method for determining the technical condition of a bridge span structure by determining its natural characteristics: actual stiffness and parameters of natural vibration forms are shown. Problem Statement. The article is devoted to the problem of practical implementation of the latest theoretical developments in the field of diagnostics of the technical condition of road bridges by conducting full-scale dynamic tests. Purpose. The main purpose of the article is to demonstrate the effectiveness of dynamic impulse testing as a method for assessing the technical condition of bridges. The method involves the excitation of vibrations of bridge structures by means of pulse loads, recording the response of the structure and analyzing the data obtained. Materials and methods. The material for this article is the results of field tests of a curved overpass made of monolithic reinforced concrete located near Kyiv. The following research methods were used: information analysis, mathematical modeling, and general methods of theoretical research.

TIME DEPENDENT DEFORMATIONS OF A COUPLED BRIDGE: A CASE STUDY

<p>The bridge's span structure comprises a connected beam designed to support a concrete slab poured over parallel steel supports. Simultaneously, segmental construction, shrinkage, and the flow of concrete play a significant role in stress redistribution over time. The span construction is statically indeterminate due to its connections with the abutments, and temporal deformations occur under additional complex conditions. In this analysis, we employed a calculation model based on the layered finite elements method developed by the authors. This model can be utilized to analyse both statically indeterminate supports and the predicted phased construction method. It accounts for changes in the static system and loading, as well as variations in the layers within the coupled section and the viscous properties of the concrete over time. The calculation analysis results reveal that viscous concrete deformations, combined with different moments of activation of individual segments, have a significant impact on stress redistribution over time. Such intricate analyses are indispensable for ensuring the required safety and cost-effectiveness of the bridge span construction.</p>

ДОСЛІДЖЕННЯ АРМАТУРИ ПЕРІОДИЧНОГО ПРОФІЛЮ А-ІІІВ ТА ПЕРСПЕКТИВИ ЇЇ ЗАСТОСУВАННЯ ДЛЯ ПЛИТ ПРОГОНОВИХ БУДОВ МОСТІВ

Introduction. Metal reinforcement A-IIIв, manufactured from reinforcement A-III in accordance with GOST 5781 by pulling, was quite widely used for slabs of span structures of bridges in the period before 1991, as well as later. There is a need to repair such structures due to the exhaustion of their resource due to a significant duration of operation, damage due to the impact of means of destruction during hostilities. Often, the best option for repairing such spans is to replace a separate plate or plates with similar ones, since in this case there are no problems with the size of height, resting on existing supports, etc. Problem Statement. The vast majority of bridges in Ukraine, built in the period 1960-1991 and, to a large extent, in subsequent years, were designed according to typical projects. A large number of these bridges were built from girder slabs according to typical designs, where class A-IIIв reinforcement was used as prestressed reinforcement. These reinforcements were produced directly at the factories producing slabs structures from reinforcements of class A-III in accordance with GOST 5781 by pulling. To perform such works, the manufacturing plant must have appropriate equipment, qualified specialists, documentation, and obtain reinforcements of the required quality. As for the documentation, in the period up to 1991, such documentation was developed centrally and distributed to factories manufacturing structures. After 1991, this does not happen, the documentation is often not updated, which can be the reason for not ensuring the quality of the structures. Purpose. To analyze the documentation for the manufacture and use of reinforcement A-IIIв for the manufacture of slabs of span structures of bridges with a length of 12 m in accordance with the documentation VTP 21-86 (addition). To research the reinforcement A-IIIв, which is manufactured in accordance with the documentation YN 218 USSR – 026-84 directly at the manufacturing plant from the reinforcement of class A-III in accordance with GOST 5781 by pulling it for further use for the manufacture of slabs of span structures of bridges with a length of 12 m in accordance with documentation VTP 21‑86 (addition). Establish the possibility of using reinforcement A-IIIв in today’s conditions for the manufacture of slabs of span structures 12 m long in accordance with the documentation VTP 21-86 (addition) for the repair and construction of bridges.

STRUCTURAL AND TECHNOLOGICAL SOLUTIONS OF STRUCTURES OF BRIDGE PROPERTY INVENTORY IN THE CONSTRUCTION OF TEMPORARY BRIDGE CROSSINGS

Purpose. Research of constructive and technological solutions for the use of inventory bridge property during the construction and temporary restoration of bridge crossings. Development of recommendations regarding the multi-purpose use of metal beams of inventory bridge property during the construction and temporary restoration of bridge crossings under normalized loads. Method. To achieve the set goal, the work was carried out: the study of structural and technological solutions for the use of inventory bridge property (Peyne beams) in the construction and temporary restoration of bridge crossings, highlighted in the literature; study and generalization of design experience and technological solutions of combining wooden structures and details with metal beams in the construction of temporary bridge crossings. The results. The result of this work is collected data on the advantages and disadvantages of using metal span structures of bridges in combination with wooden structures and elements. Analysis of the possibility of using these structures for quick restoration of bridge crossings and ensuring safe traffic. Originality. It consists in the fact that for the quick and high-quality restoration of the destroyed transport infrastructure, in particular, road and railway bridges, it is proposed to use metal beams of long-term storage inventory bridge property in combination with wooden structures and elements included in the joint work. This will make it possible to rationally use the existing reserve of materials, high rates of recovery and reliable provision of traffic of the corresponding transport. Practical value. Based on the obtained research data, it is possible to conclude that the constructive and technological solutions of the use of inventory bridge property (Peine beams) in the construction and temporary restoration of bridge crossings have a number of technological advantages that make it possible to ensure the effective restoration of railway structures destroyed by military actions in a short time. The method of combining wooden structures and elements with metal beams of span structures of the carriageway during the temporary restoration of road bridges increases their carrying capacity.

Determining the effect of reinforcing a cement-concrete coating of bridges on the stressed-strained state of structures

This paper reports a study of the cement-concrete coating on bridges using FRP reinforcement. That has made it possible to design optimal structures by selecting the height for reinforcement arrangement in the layers of a roadbed in order to ensure strength characteristics. An engineering method for calculating a hard roadbed with composite reinforcement has been devised, which makes it possible to take into consideration its work both in a joint package of the structure with a slab and separately – when it exfoliates from the slab of the bridge's span structure. Underlying this research are effort-determining methods, estimation dependences from the theory of bending layered structures, as well as dependences from elasticity theory to assess the strength of materials for a roadbed. The consideration of shear strains when designing slabs has helped establish that the deflections according to the devises method were 1.4 times larger than those in the classical approach. The method was tested by a numerical experiment, which confirmed the need to use composite reinforcement in the upper layers of a road surface on bridges, which improves its durability by 1.2 times. The results of the numerical experiment indicate that the equivalent stresses in the lower layers of a free-moving roadbed were 2.91 MPa, and, when operating in a joint assembly with a slab, they took a negative value (–0.2 MPa). Practical application of the devised calculation method makes it possible to determine the refined normal stresses in the layers of a roadbed, taking into consideration the characteristics of structure operation. Owing to this, additional opportunities open up for calculating the roadbeds of bridges whose design utilizes the most common types of span structures in the bridge industry.

AERODYNAMIC STABILITY OF BRIDGES WITH VARIOUS LEVELS OF STRUCTURAL DAMPING

Introduction: Structural damping is one of the most important parameters affecting the aerodynamic stability of bridge structures. Purpose of the study: We aimed to assess the effect that structural damping of a bridge structure has on its stability in a wind current. Methods: In the course of the study, we performed experimental studies of the aerodynamic stability in typical girder bridge structures (with two and four main girders) with different levels of structural damping, facilitated by a unique experimental unit: Large Research Gradient Wind Tunnel, courtesy of the National Research Moscow State University of Civil Engineering (NRU MGSU). Results: The results of the experimental studies show that, despite the general trend towards the decrease in the amplitude of bridge span structure oscillations as the structural damping level increases, the dependence between these parameters is nonlinear. When providing R&D support in the design of real-life structures, in case it is necessary to increase the aerodynamic stability of the superstructure by increasing the level of structural damping (changing the type of joints in structural elements, using mechanical damping devices), it is recommended to conduct experimental studies in wind tunnels to assess the effectiveness of a given solution.

ПОВТОРНЕ ВИКОРИСТАННЯ МОСТОВИХ БАЛОК В ЯКОСТІ ПРОГОНОВИХ БУДОВ ТИМЧАСОВИХ МОСТІВ

Introduction. This article presents the results of study of the quality of girders that were used for the construction of temporary road bridge. In the bridge construction practice there is a need to use girders in the construction of road bridges on local roads that can be reused in temporary bridges construction. It is important when using such structures to determine their reliability for long-term operation. The cost of bridge girders is up to 60% of the cost of a new bridge, so the reuse of utilizedsed girders is economically feasible. Utilized girders can be reused on local roads and temporary bridges. Problem statement. To determine the usability of utilized girders in temporary bridges construction and provide recommendations for the girders reuse and possible bridge design structures. Materials and methods. The following works were performed during the inspection: visual inspection of the girders at places of their storage after dismounting; measurement of the basic sizes of girders; determination of concrete strength by non-destructive test method; determination of the number of working reinforcement and the protective layer thickness; measurements of pH of concrete of a protective layer were performed; registration of existing defects was performed. The following measurements were performed during the tests: general displacements and deformations of structural elements of the structures; relative deformations of cross sections; local deformations (displacements in joints). Results. According to the results of tests and calculations, the bearing capacity of the bridge span structure was determined. After analyzing the results of experimental and theoretical studies, conclusions were made regarding the operational performance of the girders of the bridge span structure. Conclusions. Girders in the 1st, the 2nd and the 3rd technical state can be considered suitable for bridge span structures unreservedly. Girders in the 4th technical state, need repairing and reinforcement for reuse in bridge span structures. They cannot be used without repairing. Girders in the 5th technical state cannot be used in the span structures of road bridges. They can be used, for example, as transition slabs, or for pedestrian bridges and crossings, or can be used for testing the technology of bridge structures repairing. Thus, tests of bridge girders and full-size joints testify that the accepted design decision provides the needed bearing capacity of girders and of the bridge span structure as a whole. This confirms the sufficient reliability of utilized girders in the further work. Practice shows that it is also needed to pay great attention to the following: firstly- to the methods of dismantling the girders without damage; secondly — to the proper storage of girders after dismantling.

Elaboration of weatherproof steel 06гн3мд for structures of bridges exploited in coastal zone

At present decreasing of costs and increasing of efficiency are the most priority directions in any industry. Developing in this way, JSC “Ural steel” together with FGUP “CNIIchermet after I.P. Barding” had mastered production of sheet metal product with increased resistivity against atmosphere corrosion made of steel 14ХГНДЦ for construction of bridges. Because of specific chemical composition of the steel, in the process of metal structures running in the open air, a solid strong oxide film is formed on the metal of the structures which prevents further corrosion without painting. For bridge builders elimination of costly operation of painting of span structures will enable to decrease considerably the costs of bridges construction and running. Having many advantages, steel 14ХГНДЦ has some restrictions in applications for steel structures without painting, as follows: - in sea zone according to domestic norms no close than 500 m from coastline; - in case of disorderly conditions of protective film formation and/or application of salt solutions for surface cleaning (as a rule the restrictions refer to traffic area of bridge span). In view of that for JSC “Ural Steel”, as the leading producer of bridge steel in Russia, an actual task erose: to elaborate and create a weatherproof steel, which could not only operate the whole period of a bridge running without additional protection at bridges con­struction through sea areas or close to coastline, but also withstand severe climate conditions of our country, including areas of High North with temperature lower -50°С. To solve the task together with OJSC “Institute Giprostroymost” and JSC BNIIZhT, a research work was accomplished to elaborate a system of alloying new steel 06ГН3МД with nickel content ~3.0 %, as well as production modes ensuring required corrosion resistance for operation in sea zone. Results of laboratory studies of the new weatherproof steel 06ГН3МД for application in bridge structures for coastal conditions and sea areas presented. Results of mechanical, technological, corrosion as well as fatigue tests of rolling products of the elaborated steel presented. It was established by laboratory studies that the new steel is weatherproofed and ensures lower corrosion losses, higher impact toughness at negative temperatures and plasticity comparing with steels used at present. It was shown that the strength class, technology and modes of factory welding of steel 06ГН3МД meet the requirements to steel span structures of bridges. Base on the results of the studies, the chemical composition of the steel 06ГН3МД was specified, as well as modes of heat treatment, ensuring the required characteristics with significant acceding. It was established that samples of the new steel 06ГН3МД showed considerably higher corrosion resistance - in average by 20% comparing with steel 14ХГНДЦ. At that corrosion resistance tests of welded joints of the new steel showed even higher resistance of the seam comparing with the basic metal, which speaks about quality selection of welding modes and welding materials.

Relationship between the Dynamic Parameters of a Structure’s Vibration Process and the Loading Model Moving on a Bridge

A sufficiently strict conduction of supervision during bridge operation is a crucial matter for many countries, including the underdeveloped country of Viet Nam. In recent times, the budgets in developed countries used for funding the implementation of quality-assessment procedures are quite high compared to the lower budgets in underdeveloped countries. The plan proposed in this work addresses the current lack of information available in the process of structure-quality evaluation. The vibration signals will be acquired from the random circulation status to determine the structure’s behavior so as to utilize the signal information during the bridge span’s operation. The study’s main goal is to find various parameters that can be used to evaluate the actual bridge performance. These parameters must meet certain criteria, such as high sensitivity, low measurement cost, and efficiency in the measurement process, but must not affect the itinerary of vehicles moving on the bridge. The actual structural vibration signals used in this work currently serve as a best trend model for evaluating the operation of the bridge span structure. This study will focus on determining the relationship among deflection, acceleration, and vehicle load so as to evaluate the structure’s working process. This study has also fabricated an experimental model to evaluate and test the sensitivity of the parameters utilized in this study in order to verify the results obtained. The results obtained in this research will be applied for the quality-control process in several bridge models with span structures built with the composite steel concrete cross section of the beam. Many developing countries, including Viet Nam, will receive benefit in the future from the useful advantages presented in this study.

ОБ ЭФФЕКТЕ РЕГУЛИРОВАНИЯ УСИЛИЙ ИСПОЛЬЗОВАНИЕМ ВРЕМЕННОЙ НЕРАЗРЕЗНОСТИ В РАЗРЕЗНЫХ СИСТЕМАХ СТАЛЕЖЕЛЕЗОБЕТОННЫХ МОСТОВ

Abstract. The publication shows the effectiveness of applying the principle of temporary continuity by combining split span structures into acontinuous couplingusing a temporary joint. The method can be viewed as an option for effort regulation, creating abearing capacity reserveinload-bearing constructions within the span structures of bridges. The calculations provided show the effect on stress rate and bending moment in split span structurescombined into a double-spancontinuous coupling by a temporary joint.

Calculation method steel reinforced concrete continuous bridge spans with two reinforced concrete slabs on the effect of concrete shrinkage

The article is considered calculation method steel reinforced concrete continuous bridge spans with two reinforced concrete slabs on the effect of concrete shrinkage. For long-term processes that must be considered when calculating the span structures of bridges, besides creep, concrete shrinkage applies. Object of study: composite steel and concrete span beam bridge with two reinforced concrete slabs. Purpose: to develop a calculation method the cross section steel reinforced concrete bridges with two reinforced concrete slabs on the effect of concrete shrinkage considering concrete creep. Continuous spans of steel reinforced concrete bridges with two reinforced concrete slabs over intermediate supports much more economically, in terms of metal consumption, compared to steel reinforced concrete bridges with one concrete slab. Cross section of a reinforced reinforced concrete beam consists of a steel part that combined with two reinforced concrete slabs. The article presents the results of the calculation of continuous steel-concrete superstructure of a road bridge with two reinforced concrete slabs by the above method.

Dynamic reduction in the calculation of bridge structures

In modern bridge construction, on the one hand, there are increasing trends towards increasing bridge spans, which requires reducing the weight of structures. On the other hand, the use of structural elements made of various composite materials is expanding, which allows to significantly reduce the weight of the bridge structures as a whole. However, the creation of new forms of span structures of bridges requires more detailed calculations in order to optimize such forms, in particular the role of calculating the dynamic impact, because with increasing spans and weight loss, increases design flexibility and sensitivity to dynamic loads. In the present paper, the problems of solving an incomplete algebraic problem of eigenvalues and eigenvectors are considered. To increase the accuracy of the calculation and exclude the use of high-order matrices, a method of sequential reduction of the stiffness and equivalent mass matrices is proposed. The method is based on the construction of partial systems using a static transformation, followed by the solution of its own problem for the partial system. In the process of solving this problem through the eigenvectors of the system, the minor unknowns are reduced to the main ones. Dynamic reduction showed high calculation accuracy..

Substantiation of the necessity and method of upgrading the software of the measuring complex for assessing the load capacity of girder spans of road bridges

The article notes that the software of the complex used in the Russian troops to solve in a short time the actual problem of determining the possibility of safe passage of super heavy loads on girder road bridges has the following disadvantages: 1) it can only be used for split concrete bridges; 2) the decision to pass a large load through the bridge is made only by the value of the deflection in the center of the span, without taking into account the resulting stresses in the bridge span structure structures, and without taking into account the bearing capacity of the supports. In the article, in order to eliminate these shortcomings: 1) a strict formula is obtained for calculating the deflection in the middle of beam spans made of any structural materials from the angle of rotation of their support sections; 2) based on the use of the fundamental relationship between the relative heights of girder spans, the relative deformations of the edges of their cross sections and their relative deflections, it is proved that the maximum stresses in the edges of the cross sections of girder spans from any structural materials can be calculated by the maximum deflection value in the middle of their spans; 3) a method is established for determining the ability of beam bridge supports to ensure safe passage of a heavy vehicle by the nature of changing the rotation angles of the supporting cross sections of the span structures under the influence of the movement of the heavy vehicle layout. Taking these three results into account, when upgrading the software of the measurement system, ensures that the goal of the work is achieved.

Incorporation of Stress Time Dependence into Failure Projection Modeling of Corroding Bridge Post-Tensioning Tendons

Post-tensioning (PT) has evolved to become an important technology for designing long span bridge structures. However, tendon failures resulting from wire/strand corrosion have been reported as early as 2 y post construction. In response to this, a recent study introduced and evaluated an analytical modeling approach that projects corrosion-induced wire and strand fractures and tendon failures, given statistics that characterize wire corrosion rate. This past modeling effort assumed that tensile stress in tendons was constant with time at 63% of the guaranteed ultimate tensile strength (GUTS); however, in actuality this stress decreases with time over an assumed 10,000 d (approximately 27 y) from an initial value of about 70% of GUTS to a long-term value in the range 60% to 63% of ultimate at mid-span for a simply supported beam as a consequence of long-term concrete creep and shrinkage and strand relaxation. The present study builds upon this model by incorporating this time dependence of tendon stress into the failure projection modeling. Results are discussed within the context of better understanding bridge tendon integrity issues and corrosion related failure concerns.

An observation of non-stationary response to non-synoptic wind on the Forth Road Bridge

The GeoSHM project feasibility study for monitoring the Forth Road Bridge is briefly introduced and the instrumentation summarised. The events of January 9th, 2015 are described, when the bridge was struck by storm Elon, which caused widespread damage across Scotland and led to the temporary closure of the bridge when a van was blown over. During this storm an anomalous large amplitude response was observed.The data for January 9th, 2015 are analysed to show that the extreme response and the corresponding wind are non-stationary and non-Gaussian. Further analysis of the rainfall radar data for the same time shows a line of intense rainfall extending for over 100 ​km, which passes the site of the bridge at exactly the time of the peak response. The rainfall intensity was high enough to indicate that this feature was caused by convective activity and this observation was corroborated by records of lightning strikes. It is concluded that non-stationary wind events can give rise to large response of long span bridge structures and that this response can exceed that observed from the stationary wind field. Furthermore, historical data confirm that energetic squall lines are not uncommon in the UK. Therefore, the assumption of stationarity in predicting the wind induced response of long span bridges may be non-conservative and the climatology of large convective systems, such as squall lines, should be considered in assessing the wind hazard for these structures.

Strain Data Analysis of Small and Medium Bridge Structures Based on Finite Element

Structural health monitoring technology is increasingly used in the operation and management of small and medium span bridge structures, which also brings the problem that it is difficult to fully interpret and utilize the mass monitoring data. In this paper, the Sanyang Bridge is used as the engineering background, based on the strain monitoring data, combined with the finite element calculation software MIDAS/civil, to evaluate and analyze the operating state of the bridge structure. The results show that the overall operation status of Sanyang Bridge is good, the evaluation method combining finite element calculation and monitoring data is reasonable, this method can be applied to data processing and condition assessment of small and medium span bridges.

Carrying capacity of reinforced concrete beams of the compound cross-section of the span structures of bridges, extended by the paving slab

Problem. Experimental studies of load-carrying capacity of full-scale reinforced concrete bridge beams of typical 56 type project are described. The beams were dismantled from the existing bridge after 40 years of its operation and combined with fragments of precast-monolithic and precast ribbed paving slab, were used during the reconstruction of the old span structures for widening and simultaneous strengthening of their beams by way of extending the transverse section from above. Goal. Three prototypes of full-length reinforced concrete bridge beams with a total length of 14,06 m were tested, which had a folded cross-section, including a tare section of an existing beam of 0,85 m high and a fragment of a ribbed precast or precast monolithic plate, extended from above for joint work. Thus, the total height of the folded section of the reinforced prototype beams was 1,27…1,29 m. Methodology. The technique of testing the beams of the composite section was to obtain the maximum number of experimental data on a limited number of prototypes, in particular their carrying capacity for normal and inclined cross-sections. For this purpose, during the tests, different schemes of their loading with one or two concentrated forces were created for obtaining different types of destruction on the same prototype – by bending moment and transverse force. Originality. Therefore, the load-carrying capacity of the test beams in both normal and inclined cross-sections were studied. The main purpose of these studies is to evaluate the impact of the inclusion in the joint work with the existing beams of ribbed paving slab on the increase of their carrying capacity both in zonal moment and in transverse force compared with the carrying capacity of the only existing beams. Results and practical value. As the main result of the research, it was found that after the inclusion in the joint work of the ribbed paving slab the carrying capacity of normal and inclined cross-sections increased by 1,55-1,65 times, which is sufficient to provide load capacity of the expanded paving slab of bridge structures.